SLIDING SEAT MECHANISM AND LATCH THEREFOR

Abstract: A sliding seat mechanism for a vehicle seat comprises transversely spaced fixed floor runners (10, 12) within which slide co-operating seat runners (14, 16) fixed to the underneath of the seat. Respective pivotally mounted latches (22, 40) are carried by the seat runners (14, 16) for latching engagement within apertures in respective floor runners (10, 12). The latches are movable from their latched to their unlatched positions by means of respective release levers (58, 60) which are themselves biased to an inoperative position in which the latch members are movable from their unlatched to their latched positions independent of the release levers.

Description: Title: Sliding Seat Mechanism and Latch Therefor This invention relates to a sliding seat mechanism such as may be provided for a motor vehicle and to a latch mechanism for restraining the seat against sliding movement relative to the vehicle. Sliding seat mechanisms have been used for many years in motor vehicles and typically comprise a pair of laterally spaced runners secured to the vehicle floor and a seat mounted on a pair of laterally spaced rails each of which slides on or in a respective runner. Many differing forms of latching mechanism have been proposed for ensuring that sliding movement of the seat rails relative to the runners is only possible when the latch is positively released by the user. A typical arrangement is for one or both of the floor mounted runners to be provided with a series of longitudinally spaced apart apertures within which a spring biased pivotal latch carried by the seat or seat rails is selectively engageable. Thus when the latch is engaged in an aperture or apertures the seat is restrained against sliding movement longitudinally of the runners i.e. the seat is restrained against forward and rearward movement relative to the vehicle. Typically such a latch has included a release lever, readily accessible by the user at the front or side of the seat, operable to disengage the latch and permit the seat to be adjusted longitudinally on its runners. Such a release lever is usually either integral with or permanently connected to the latch and, when released by the user after sliding adjustment of the seat, permits the latch to pivot into locking engagement with the most adjacent aperture in an associated runner. Frequently, after release of the release lever, the latch is positioned intermediate adjacent apertures abutting a part of the runner between such apertures. The latch then engages with the most adjacent aperture only upon a further small sliding movement of the seat i.e. the seat is usually slid by the user until the latch engages under its spring bias into the most readily engageable aperture. Sometimes however the user inadvertently leaves the latch disengaged from an aperture resting on a part of the runner between adjacent apertures whereby the seat is then free to slide under the influence of external forces until the latch reaches a location at which it will engage under its spring bias into an aperture. Such pivotal latching movement of the latch also causes movement of its integral or connected release lever so that, in order for the latch to engage in an aperture when the seat is moved under external forces, the spring force biasing the latch has to overcome the inertia not only of the latch but also of the integral or interconnected release lever. The relatively high inertia of the latch/release lever assembly can cause problems in that when the latch has been left in a disengaged position severe deceleration or acceleration of the vehicle may cause the latch to "skip" one or more or all of the apertures as the seat rails move rapidly relative to the runners. This possibility is an unacceptable safety hazard and it is an object of the invention to provide a sliding seat mechanism and latch therefor which will mitigate against this problem. In accordance with one aspect of the invention there is provided a sliding seat mechanism for a vehicle seat comprising at least one first runner member securable in fixed relationship to a part of a vehicle at which a seat is to be mounted; at least one second runner member securable in fixed relationship to a said seat, said runner members being engaged with one another for relative sliding movement therebetween whereby when said first runner member is secured in a vehicle and said second runner member is secured to a seat the seat may slide to and fro in the vehicle; a latch member mounted on or adjacent one of said runner members with spring means biasing a latch element of said latch member towards the other said runner member so as to be engageable with an aperture therein; and release means mounted on or adjacent said one runner member operable independently of said latch member to engage it and move it against the bias of its spring means out of engagement with said aperture, said release means being biased to an inoperative position wherein the latch member is movable from its unlatched to its latched positions independent of said release means. Typically the latch member and the release means therefor are mounted on or adjacent said second runner member, and said first runner member is provided with a plurality of spaced apart said apertures therein. The latch member may be pivotally mounted about a pivot axis which is parallel to the axes of the runner members so that a latch element of the latch member is movable into engagement with and disengagement from a said aperture in a direction laterally of the runner members. Alternatively the latch member may be pivotally mounted about a pivot axis which is normal or otherwise inclined to the axes of the runner members. Said release means may comprise a release lever which is conveniently mounted for rotation about a pivot axis which is parallel to the axes of the runner members and the pivot axis of said release lever may be coaxial with the pivot axis of said latch member. Alternatively, the release means may comprise a release lever mounted for rotation about a pivot axis which is normal to the axes of the runner members. The release lever preferably has an operating part or handle which is accessible to the user at the front or side of the seat. The lever may include an actuating part engageable, upon rotation of the release lever against its bias, to engage the latch member to pivot it out of its latched position. There is sufficient clearance between the actuating part of the release lever and that part of the latch member engageable thereby to ensure that, in the inoperative position of the release lever, there is no possibility of contact between said actuating part and any part of the latch member in either the latched or unlatched positions thereof. Conveniently the latch element of the latch member comprises a plurality of teeth engageable in a corresponding plurality of adjacent apertures in said first runner member. Conveniently the latch member and the release lever are both mounted on said second runner member. Typically a pair of parallel spaced apart first runner members are mounted in fixed relationship on a vehicle and a pair of co-operating parallel spaced apart second runner members are mounted on a vehicle seat. Preferably a said latch member is pivotally mounted on each of said second runner members for latching engagement with one or more apertures in a respective said first runner member. A first said release lever directly operable by a user may be mounted adjacent a first one of said latch members, and a second release lever may be mounted adjacent a second one of said latch members, said second release lever being operable via a cable or like link by said first release lever whereby both of said latch members may be moved out of engagement with respective apertures by user operation of said first release lever. Said second latch member is movable from its unlatched to its latched positions independently of said second release lever. Said first and second release levers of the release means may be interconnected by a rigid stirrup portion disposed adjacent the front of a seat and extending transversely thereof. In such an arrangement, lifting of the stirrup portion by a user will pivot the release levers upwardly to engage the respective latch members to pivot them out of their latched positions. Instead of a lever the release means may comprise a cable system operable by a user to cause an actuating element thereof to engage one of the latch members and move it from its latched to its unlatched position. Other features of the invention will become apparent from the following description given herein solely by way of example with reference to the accompanying drawings wherein:- Figures 1 to 3 comprise a series of somewhat diagrammatic front views of a sliding seat mechanism and latches constructed in accordance with the invention wherein Figure 1 shows the latches in their fully engaged latched positions, Figure 2 shows the latches in their fully disengaged unlatched positions and Figure 3 shows the latches in intermediate unlatched positions; Figure 4 is a top plan view of the mechanism showing the latches in the fully engaged positions of Figure 1; Figure 5 is a side elevation view of the mechanism showing one of the latches and the release lever; Figure 6 is a top plan view of one of the latches; Figure 7 is a diagrammatic front view of another embodiment of release means as shown in more detail in Figure 8; and Figure 8 is a top plan view, somewhat similar to that of Figure 4, but showing a different embodiment of release means for the latch members. Referring to Figures 1 to 4 there is shown a seat adjuster mechanism comprising two parallel spaced apart elongate floor runners 10 and 12 which in use would be fixedly secured to the floor of a vehicle. Each floor runner 10, 12 is of channel section form having an open top, opposed side walls and a base portion through which may pass bolts (not shown) for securing the runners to the vehicle floor. A seat (not shown) is mountable for sliding movement relative to the floor runners 10 and 12 by means of a pair of parallel spaced apart elongate seat runners 14 and 16 each of which is co-operatively engaged with a respective floor runner 10 and 12. Each seat runner includes a vertically disposed web part and lower divergent limbs engaged between the walls of a respective floor runner and slidable relative thereto on ball races 18. Each seat runner 14, 16 is securable to the underside or side of a seat by mechanical fastenings (not shown) whereby the seat may slide on the floor runners 10 and 12 in a direction fore and aft of the vehicle in which the seat is mounted. Referring to Figure 5, each of the floor runners 10 and 12 (only the runner 10 being shown in Figure 5) includes a plurality of longitudinally spaced apart apertures 20 which, in the embodiment illustrated, are of square configuration. A latch member 22 and a release lever 24 therefor are shown in Figure 5 wherein the latch member and the release lever are mounted for rotation about respective pivot axes parallel to the longitudinal axes of the runners 10 and 14. The latch member 22 comprises a metal pressing having laterally spaced arms 26 with coaxial circular apertures 28 formed therein whereby it may be pivotally mounted for rotation on a pivot shaft 29. The latch member 22 includes a plurality, in this case three, latch teeth 30 at its lower edge which project towards the apertures 20 in the floor runner so as to be engageable therein in the latched position of the latch member 22. A coil torsion spring 32 (see Figure 4) mounted about the pivot shaft 29 biases the latch member 22 towards its said latched position. The release lever 24 comprises a pivot shaft mounted for rotation in bearings 31 and extends in a direction forwardly of the seat runner 14 terminating in a cranked handle portion 34 whereby the user may rotate the shaft about its pivot axis. The release lever includes an actuating part in the form of a cranked rearward extension 38 which is engageable with an upper part of the metal pressing comprising the latch member 22. Referring to Figures 1 to 3 the release lever 24 and the latch 22 are shown at the lefthand side of each drawing whereas a corresponding latch 40 is shown at the righthand side of each drawing. The latch 40 is of identical configuration to that of the latch 22 and is pivotally mounted for rotation about a pivot shaft 41. The latch 40 is biased by a torsion spring 44 towards latching engagement with apertures provided in the floor runner 12. A release lever 42 comprises a pivot shaft mounted for rotation in bearings 43 and is biased by a torsion spring 46 towards an inoperative position. The latch 40 is movable out of its latching position by an actuating part of the release lever 42 in the form of a cranked rearward extension 48, which is itself actuated by a cable or like link 50 upon rotation of the user operated release lever 24 as will be further described below. Referring again to Figure 1, each of the two latches 22 and 40 is shown in its fully engaged latched position with the latch teeth 30 engaged within respective adjacent apertures 20 in the respective floor runners 10 and 12. The release levers 24 and 42 are biased by the single spring 46 to their inoperative positions and the latches are biased by their respective springs 32 and 44 towards their latched positions. To disengage the latches from the floor runner apertures and permit slidable adjustment of the seat runners relative to the floor runners the release lever 24 is rotated by the user against its spring bias from the position shown in Figure 1 to the position shown in Figure 2. As a result of this rotation the actuating part 38 of the release lever 24 is caused to abut the upper part of the latch 22 causing it to rotate counter-clockwise i.e. in the same direction as the release lever, to pivot the latch 22 to its fully unlatched position with the teeth 30 withdrawn laterally out of the apertures 20 in the floor runner 10. A corresponding clockwise rotation is imparted to the actuating part 48 of the release lever 42 and latch 40 by means of the cable or like tension link 50 connected between a bracket 52 fast with the lever 24 and a bracket 54 fast with the release lever 42. Upon completion of any required sliding adjustment of the seat the user would release the release lever 24 so that both levers 24 and 42 return to their inoperative positions as shown in Figure 1 under the bias of the spring 46. It sometimes occurs that upon return of the release levers to their inoperative positions, one or each of the latches 22 and 40 may remain in an intermediate unlatched position with its teeth resting upon a part or parts of the respective floor runner intermediate the apertures 20 as shown in Figure 3. However, upon subsequent sliding movement of the seat runners relative to the floor runners, such as may be occasioned during severe acceleration or deceleration of a vehicle, the latches 22 and 40 will be spring biased to engage in the most adjacent apertures in the respective floor runners 10 and 12 under the action of their respective springs 32 and 44. As will be clearly seen from Figure 3, the latches 22 and 40 may pivot from their intermediate unlatched positions to their fully engaged latched positions quite independent of and without contact with any part of their release levers 24/38 and 42/48. Thus the latches may snap into their fully latched positions with their springs 32 and 44 only having to overcome the inertia of the latches themselves. In Figures 7 and 8 of the drawings there is shown another embodiment of the release means for the latch members 22 and 40 of a sliding seat mechanism constructed in accordance with the invention wherein like reference numerals refer to like parts hereinbefore described. In the embodiment of Figures 7 and 8 each of the latch members 22 and 40 is provided with a generally horizontally extending tab or lip 56 at its upper end, the respective lips on the two latch members projecting in a direction transversely of the respective runners 10, 14 and 12, 16 and towards one another. The release means comprises a pair of release levers 58 and 60 interconnected at their forward ends by a rigid stirrup portion 62 extending transversely of the runners adjacent the front of the seat whereby an occupant of the seat may readily grasp the stirrup portion 62 to operate the release levers 58 and 60. The stirrup portion 62 is conveniently formed integral with the two release levers 58 and 60 and is of rod-like material so as to provide a generally U-shape structure of which the release levers comprise the limbs and extend parallel to the respective runners 10, 14 and 12, 16 with each lever extending underneath a lip 56 of a respective latch member 22 and 40. Each lever 58, 60 is cranked at its rearward end or is otherwise provided with bearing means so as to be pivotable about a horizontal axis extending normal to the longitudinal axes of the floor and seat runners. As shown in Figure 8 the rearward end of each lever 58 and 60 comprises a cranked portion 64 extending perpendicular to the longitudinal axes of the levers and constituting a pivot pin freely rotatable in an aperture in a respective seat runner 14 and 16. The two levers 58 and 60 are biased to inoperative positions either under the force of gravity or by spring means (not shown). At the position where each lever 58, 60 extends underneath a lip 56 of a respective latch member 22, 40, the lever may be bowed upwardly as shown at 66 in Figure 7 so that an upper surface of such bowed portion 66 is located underneath but not in contact with a said lip 56 on a respective latch member. Thus to release the latch members 22, 40 from their latched positions wherein their latch elements are engaged in respective apertures 20 in the floor runners 10 and 12, a seat occupant may grasp the stirrup portion 62 and raise it to raise the levers 58 and 60 about their pivot axes. This upwardly pivoting movement of the release levers will bring the upper surfaces of the bowed portions 66 into engagement with the underside of the lips 56 of the respective latch members 22 and 40 causing them to pivot about their own pivot axes against their spring bias from their latched positions to their unlatched positions. The seat may then be adjusted and the stirrup portion 62 released so that the release levers 58 and 60 may return to their inoperative positions either under the force of gravity or spring means. Thus, in a similar manner to that hereinbefore described, if the latch members 22 and 40 are inadvertently left in an unlatched position in a position similar to that shown in Figure 3, further relative movement between the seat and floor runners will cause immediate movement of the latch members 22 and 40 into their latched positions under the influence of their spring means without any contact between the latch members and the release levers 58 and 60. The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims: CLAIMS 1. A sliding seat mechanism for a vehicle seat comprising at least one first runner member (10 or 12) securable in fixed relationship to a part of a vehicle at which a seat is to be mounted; at least one second runner member (14 or 16) securable in fixed relationship to a said seat; said runner members (10, 14 and 12, 16) being engaged with one another for relative sliding movement therebetween whereby when said first runner member is secured in a vehicle and said second runner member is secured to a seat, the seat may slide to and fro in the vehicle; a latch member (22, 40) mounted on or adjacent one of said runner members with spring means biasing a latch element of said latch member towards the other said runner member so as to be engageable with an aperture therein; characterised in that release means (24, 38; 42, 48; 58, 60) are mounted on or adjacent said one runner member and are operable independently of a said latch member to engage it and move it against the bias of its spring means out of engagement with a said aperture, said release means being biased to an inoperative position wherein the latch member is movable from its unlatched to its latched positions independent of said release means. 2. A sliding seat mechanism as claimed in claim 1 further characterised in that the latch member and the release means therefor are mounted on or adjacent said second runner member (14, 16), and said first runner member (10, 12) is provided with a plurality of spaced apart said apertures (20) therein. 3. A sliding seat mechanism as claimed in either one of claims 1 or 2 further characterised in that the latch member is pivotally mounted about a pivot axis which is parallel to the axes of the runner members (10, 12, 14, 16) so that a latch element of the latch member is movable into engagement with and disengagement from a said aperture in a direction laterally of the runner members. 4. A sliding seat mechanism as claimed in either one of claims 1 or 2 further characterised in that the latch member is pivotally mounted about a pivot axis which is normal or otherwise inclined to the axes of the runner members (10, 12, 14, 16). 5. A sliding seat mechanism as claimed in any one of claims 1 to 4 further characterised in that said release means comprises a user-operable release lever (24, 42) mounted for rotation about a pivot axis which is parallel to the axes of the runner members (10, 12, 14, 16). 6. A sliding seat mechanism as claimed in claim 5 further characterised in that the pivot axis of the release lever is coaxial with the pivot axis of the said latch member. 7. A sliding seat mechanism as claimed in any one of claims 1 to 4 further characterised in that said release comprises a user-operable release lever (58, 60) mounted for rotation about a pivot axis which is normal to the axes of the runner members (10, 12, 14, 16). 8. A sliding seat mechanism as claimed in any one of claims 1 to 4 further characterised in that said release means comprises a user-operable cable system. 9. A sliding seat mechanism as claimed in any one of the preceding claims further characterised in that a pair of parallel spaced apart first runner members ( 10, 12) are mountable in fixed relationship on a vehicle and a pair of co-operating parallel spaced apart second runner members ( 14, 16) are mountable on a vehicle seat, a said latch member (22, 40) being pivotally mounted on each said second runner member for latching engagement with one or more apertures (20) in a respective said first runner member. 10. A sliding seat mechanism as claimed in claim 9 further characterised in that a user-operable first said release lever (24, 38) is mounted adjacent a first said latch member (22) and a second said release lever (42, 48) is mounted adjacent a second said latch member (40), said second release lever being operable via a cable or like link by said first release lever whereby both latch members (22, 40) may be moved out of engagement with respective apertures by user operation of said first release lever. 11. A sliding seat mechanism as claimed in claim 9 further characterised in that a first said release lever (58) is mounted adjacent a first said latch member (22) and a second said release lever (60) is mounted adjacent a second said latch member (40), said release levers being interconnected by a user-operable rigid stirrup portion (62) whereby both of said latch members (22, 40) may be moved out of engagement with respective apertures by user operation of said stirrup portion. 12. A sliding seat mechanism as claimed in any one of the preceding claims further characterised in that the release means is biased to its said inoperative position by spring means or under the force of gravity.

Inventors: SMITH RODGER GORDON, SMITH, RODGER, GORDON
Applicants: JOHNSON CONTROLS AUTOMOTIVE UK, SMITH RODGER GORDON, JOHNSON CONTROLS AUTOMOTIVE (UK) LIMITED, SMITH, RODGER, GORDON
Application year: 1994
Main classification: B60N2
IPC codes: B60N2